1. Field of the Invention
The present invention pertains to an apparatus for traversal through a fluid transmission pipeline and for providing an annular sealed test space for pressure testing selected sections of the pipeline. The apparatus is remote controlled and utilizes flow of pipeline fluid through the apparatus for providing power to pressurize the test space and spaced apart annular seals which define the sealed test space.
2. Background
Fluid transmission pipelines require periodic pressure testing to determine the integrity of the pipe or to locate suspected leaks. Examples of prior art pipeline testing apparatus comprise the devices described in U.S. Pat. Nos. 3,483,895 to Barto, 3,690,348 to Patterson, 3,834,422 to Larson and 4,602,659 to Parkyn. The devices described in all but the Larson patent require the use of two of the devices described for isolating a section of pipeline for pressure testing or the device must be used in conjunction with a pipeline valve at a particular location already existing in the pipeline to isolate the test section. In this latter instance a significantly long section of pipeline may be required to be pressurized for the test procedure and the complexity of using two of the line blocking "valves" as described in these references is difficult to manage in many instances. Accordingly, there has been a need for a device which will isolate a selected section of pipeline for pressurization, which device may in itself be moved along the line to various predetermined positions for pressure testing the selected small sections of the pipeline.
Another problem associated with so-called travelling valves for pipelines is the provision of onboard power for operating the seals to inflate and deflate and to provide fluid for accomplishing the pressure testing and seal actuation. It is to this end among other objectives that the present invention has been developed.